engleski

Outbreak of gangrenous mastitis in cows

Mastitis is an economically important disease and the common cause of culling of diary cows. Staphylococcus aureus is a major pathogen of the mammary gland and a common cause of contagious bovine mastitis. Infection during early lactation may result in the peracute form with gangrene of the udder. We present an outbreak of gangrenous mastitis in three primiparous heifers and one cow. The animals were kept in one stable in northwestern Croatia, together with other 50 Holstein Frisian cows and heifers. One 2, 5 year old heifer was presented to the veterinarians from the Clinic for Infectious Diseases, Faculty of Veterinary Medicine, Zagreb, Croatia, day after parturition with the history of teat discoloration that was noted two days ago. Two more cases of gangrenous mastitis in primiparous heifers at parturition were reported in the last three months in the same stable. Both were in a peracute form and with a lethal outcome. At clinical examination first quarter teat was swollen, with dark blue to black discoloration spreading ten centimeters to the lateral side of the udder. Affected parts were cold, non painful and marked with light red demarcation line. Small amounts of serous bloody fluid were spontaneously dropping from the ductus papillaris. At the basis of the second quarter teat two half moon–shaped, dark blue discolorations were also noted. Body temperature was 38, 9 ˚C, heart rate 105, respiration rate 37, and ruminations were weak. Haematological and biochemical findings were within normal range. Bacteriological cultures of milk samples were performed and isolated bacteria were identified as follows ; Streptococcus uberis from the first quarter, Staphylococcus aureus from the second, Streptococcus uberis from the third, while fourth quarter sample was negative. The same animal had a difficult parturition with a laceration of uterus and vagina so segregation and culling was recommended. Three weeks later, 8 years old cow in a late pregnancy developed similar bluish changes at the border between third and fourth quarter. They were partially surrounded by 0, 5 cm red granulation area. Since this cow was in a dry period samples for bacteriological examination were not taken. Treatment based on antibiogram of previously isolated microorganism was prescribed and consisted of 12 days of intramuscular application of penicillin, neomycin and trimethoprim. Infected animals were segregated and disinfection of stable and milking machine were conducted. Recommendations for hygienic washing and drying of udders before milking, regular milk machine maintenance were given to the owner. On the 12th day of therapy gangrenous changes were almost completely healed. In following three months there were no new cases of gangrenous mastitis in the herd. Lacking of early diagnosis and farmer's awerness of proper control measures can lead to the oubrek of gangrenous mastitis. Aldough prognossis is doubtful, treatment with targeted antibiotics evan without surgical intervention can be sucesfull.

outbreak; gangrenous mastitis; cows

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